1. Technical Field
The present disclosure relates to a power transmission interrupting device and a limited-slip differential.
2. Description of Related Art
Among differential gears that allocate power to the left and right wheels of a vehicle allowing for differential motion thereof, some are equipped with a positive clutch for limiting the differential motion of rotating members that are rotatable relative to each other (e.g., see Japanese Patent Application Publication No. 2010-84930).
The differential gear described in JP 2010-84930 A has a differential case, a pair of pinion gears rotatably supported on a pinion shaft that is fixed to the differential case, a pair of side gears meshing with the pair of pinion gears with the gear axes orthogonally crossed, an interrupting member disposed so as to be movable in the axial direction while engaged in a hole formed in the differential case in a rotation direction, and an actuator that moves the interrupting member in the axial direction.
The interrupting member has engaging teeth engaging with one side gear of the pair of side gears, and rotates with the differential case. The actuator has an electromagnet and a movable member that moves in the axial direction under a magnetic force of the electromagnet. The electromagnet is composed of a magnet coil and a core disposed so as to surround the magnet coil. The movable member is composed of a plunger made of a soft magnetic material, and a ring that is made of a non-magnetic material and prevents magnetic flux of the electromagnet from leaking to the differential case. The movable member is disposed inside the electromagnet, and the electromagnet and the interrupting member are disposed side by side in the axial direction.
When current is applied to the electromagnet, the plunger moves toward the interrupting member, causing the ring to press the interrupting member through a plate fixed to the interrupting member. Under this pressing force, the interrupting member moves in the axial direction and engages with the one side gear. Thus, relative rotation of the differential case and the one side gear is restrained, and differential rotation of the pair of side gears is also restrained accordingly.